This presentation contains 1. types and sources of air pollutants 2. effects of air pollution 3. common devices used to control air pollution 4. pollution control acts in India 5. pollution monitoring bodies in India

1. AIR
POLLUTION

2. What is pollution?
Pollution is an undesirable change in the physical, chemical or
biological characteristics of air, water and soil that may
harmfully affect the life or create potential health hazard of
any living organism.
It is a direct or indirect change in any component of the
biosphere.

3. What are pollutants?
Any substance which causes pollution is called a pollutant.
A Pollutant may thus include any chemical or geochemical
(dust, sediment, grit etc.) substance, biotic component or its
product, or physical factor (heat) that is released intentionally
by man into the environment in such a concentration that
may have adverse harmful or unpleasant effects.

4. Types and sources of air pollutants
An air pollutant is known as a substance in the air that can cause harm
to humans and the environment.
Pollutants can be in the form of solid particles, liquid droplets, or gases.
In addition, they may be natural or man-made.

5. Pollutants can be classified as either
PRIMARY POLLUTANTS
primary pollutants are substances
that are directly emitted from a
process, such as ash from a
volcanic eruption, the carbon
monoxide gas from a motor
vehicle exhaust or sulphur dioxide
released from factories.
SECONDARY POLLUTANTS
Secondary pollutants are not
emitted directly.
Rather, they form in the air when
primary pollutants react or
interact.
An important example of a
secondary pollutant is ground
level ozone — one of the many
secondary pollutants that make
up photochemical smog.

7. Major primary pollutants are:
i. Sulphur oxides (SOx):
SO2 is produced by volcanoes and in
various industrial processes. Since coal
and petroleum often contain sulphur
compounds, their combustion generates
sulphur dioxide.
Further oxidation of SO2, usually in the
presence of a catalyst such as NO2,
forms H2SO4, and thus acid rain.

8. ii. Nitrogen oxides (NOx):
nitrogen dioxide are emitted
from high temperature
combustion.
Nitrogen dioxide is the chemical
compound with the formula
N02. It is responsible for
photochemical smog, acid rain
etc.

9. iii. Carbon
monoxide:
It is a colourless,
odourless, non-
irritating but very
poisonous gas.
It is a product by
incomplete
combustion of fuel
such as natural gas,
coal or wood.
Vehicular exhaust is a
major source of
carbon monoxide.

10. iv. Carbon dioxide
(CO2):
A greenhouse gas
emitted from
combustion but is
also a gas vital to
living organisms.
It is a natural gas in
the atmosphere.

11. v. Volatile organic compounds:
VOCs are an important outdoor air pollutant. In this field they are often
divided into the separate categories of methane (CH4) and non-
methane (NMVOCs).
Methane is an extremely efficient greenhouse gas which contributes to
enhanced global warming.

12. vi. Particulate matter:
particulate matter (PM) or fine particles, are tiny particles of solid or
liquid suspended in a gas.
Sources of particulate matter can be manmade or natural.
Some particulates occur naturally, originating from volcanoes, dust
storms, forest and grassland fires, living vegetation, and sea spray.
Human activities, such as the burning of fossil fuels in vehicles, power
plants and various industrial processes also generate significant
amounts of aerosols.
Increased levels of fine particles in the air are linked to health hazards
such as heart disease, altered lung function and lung cancer

14. vii. Persistent free radicals
viii. Toxic metals – such as lead, cadmium and copper.
ix. Chlorofluorocarbons (CFCs) – harmful to the ozone layer emitted from
products currently banned from use.
x. Ammonia (NH3) – emitted from agricultural processes. It has a pungent
odour. Ammonia contributes significantly to the nutritional needs of
terrestrial organisms by serving as a precursor to foodstuffs and fertilizers.
Although in wide use, ammonia is both caustic and hazardous.
xi. Odours – such as from garbage, sewage, and industrial processes
xii. Radioactive pollutants – produced by nuclear explosions, war
explosives, and natural processes such as the radioactive decay of radon.

15. Secondary pollutants include:
i. Particulate matter formed from gaseous primary pollutants and
compounds in photochemical smog. Smog is a kind of air pollution;
the word “smog” is a portmanteau of words smoke and fog.
ii. Classic smog results from large amounts of coal burning in an area
caused by a mixture of smoke and sulphur dioxide.

16. III. Modern smog does not usually come from coal but from vehicular
and industrial emissions that are acted on in the atmosphere by
sunlight to form secondary pollutants that also combine with the
primary emissions to form photochemical smog.
IV. Ground level ozone (O3) formed from NOx and VOCs. Ozone (O3) is
a key constituent of the troposphere (it is also an important
constituent of certain regions of the stratosphere commonly known
as the Ozone layer).

17. Sources of Air Pollution:
Sources of air pollution refer to the various locations, activities or
factors which are responsible for the releasing of pollutants in the
atmosphere. These sources can be classified into two major categories
which are:
 anthropogenic sources
 natural sources

18. Anthropogenic sources (human activity) mostly related to
burning different kinds of fuel:
i. smoke stacks of power plants, manufacturing facilities (factories) and waste
incinerators, as well as furnaces and other types of fuel-burning heating devices.
ii. motor vehicles, marine vessels, aircraft and the effect of sound etc.
iii. Chemicals, dust and controlled burn practices in agriculture and forestry
management.
iv. Fumes from paint, hair spray, varnish, aerosol sprays and other solvents.
v. Waste deposition in landfills, which generate methane.
vi. Military, such as nuclear weapons, toxic gases, germ warfare and rocketry.

19. Natural sources:
i. Dust from natural sources, usually large areas of land with little or no
vegetation.
ii. Methane, emitted by the digestion of food by animals, for example cattle.
iii. Radon gas from radioactive decay within the Earth’s crust. Radon is a
colourless, odourless, naturally occurring, radioactive noble gas that is
formed from the decay of radium. It is considered to be a health hazard.
Radon gas from natural sources can accumulate in buildings, especially in
confined areas such as the basement and it is the second most frequent
cause of lung cancer, after cigarette smoking.
iv. Smoke and carbon monoxide from wildfires.
v. Volcanic activity, which produce sulphur, chlorine, and ash particulates.

20. Effects of Air Pollutants:
i. Carbon monoxide (source-
Automobile exhaust,
photochemical reactions in the
atmosphere, biological oxidation by
marine organisms, etc.)-
ii. Affects the respiratory activity as
haemoglobin has more affinity for
CO than for oxygen. Thus, CO
combines with HB and thus
reduces the oxygen-carrying
capacity of blood. This results in
blurred vision, headache,
unconsciousness and death due to
asphyxiation (lack of oxygen).

21. ii. Carbon di oxide (source- Carbon burning of fossil fuels, depletion of
forests (that remove excess carbon dioxide and help in maintaining the
oxygen-carbon dioxide ratio) – causes global warming.
iii. Sulphur dioxide (source- Industries, burning of fossil fuels, forest
fires, electric generation plants, smelting plants, industrial boilers,
petroleum refineries and volcanic eruptions)- Respiratory problems,
severe headache, reduced productivity of plants, yellowing and
reduced storage time for paper, yellowing and damage to limestone
and marble, damage to leather, increased rate of corrosion of iron,
steel, zinc and aluminium.

22. iv. Hydrocarbons Poly-nuclear Aromatic Compounds(PAC) and Poly-
nuclear Aromatic Hydrocarbons(PAH) (source- Automobile exhaust and
industries, leaking fuel tanks, leaching from toxic waste dumping sites
and coal tar lining of some water supply pipes)- Carcinogenic (may
cause leukaemia).
v. Chloro-fluoro carbons (CFCs) (source- Refrigerators, air conditioners,
foam shaving cream, spray cans and cleaning solvents)- Destroy ozone
layer which then permits harmful UV rays to enter the atmosphere. The
ozone layer protects the earth from the ultraviolet rays sent down by
the sun. If the ozone layer is depleted by human action, the effects on
the planet could be catastrophic.

23. vi. Nitrogen Oxides (source- Automobile exhausts, burning of fossil
fuels, forest fires, electric generation plants, smelting plants, industrial
boilers, petroleum refineries and volcanic eruptions)- Forms
photochemical smog, at higher concentrations causes leaf damage or
affects the photosynthetic activities of plants and causes respiratory
problems in mammals.
vii. Particulate matter Lead halides (lead pollution) (source- Combustion
of leaded gasoline products) – Toxic effect in man.
viii. Asbestos particles (source- Mining activities) – Asbestosis – a
cancerous disease of the lungs.
ix. Silicon dioxide (source- Stone cutting, pottery, glass manufacturing
and cement industries) – Silicosis, a cancerous disease.
x. Mercury (source- combustion of fossil fuel & plants)-brain & kidney
damage.

24. • Air pollutants affect plants by entering through stomata (leaf pores
through which gases diffuse), destroy chlorophyll and affect
photosynthesis. During the day time the stomata are wide open to
facilitate photosynthesis. Air pollutants during day time affect plants by
entering the leaf through these stomata more than night.

25. Control of Air Pollution:
The following items are commonly used as pollution control devices
by industry or transportation devices.
They can either destroy contaminants or remove them from an
exhaust stream before it is emitted into the atmosphere.

26. Mechanical collectors (dust cyclones, multi-cyclones)-
Cyclonic separation is a method of removing particulates from an air, gas or
water stream, without the use of filters, through vortex separation.
Rotational effects and gravity are used to separate mixtures of solids and
fluids.

27. Electrostatic Precipitators:
An electrostatic precipitator (ESP), or electrostatic air cleaner is a
particulate collection device that removes particles from a flowing gas
(such as air) using the force of an induced electrostatic charge.
Electrostatic precipitators are highly efficient filtration devices that
minimally impede the flow of gases through the device, and can easily
remove fine particulate matter such as dust and smoke from the air
stream.

28. IMAGE 1 Shows the
working principle of ESP.
IMAGE 2 and 3 is
complete ESP machine.
1. 2.
3.

29. Particulate Scrubbers:
The term Wet scrubber describes a
variety of devices that remove pollutants
from a furnace flue gas or from other gas
streams. In a wet scrubber, the polluted
gas stream is brought into contact with
the scrubbing liquid, by spraying it with
the liquid, by forcing it through a pool of
liquid to remove the pollutants.

30. POLLUTION CONTROL ACTS AND POLLUTION MONITORING BODIES OF INDIA:
• Constitution has incorporated provisions for protection and
improvement of environment.
• Article 48-A has been listed in the Directive Principles of State Policy
in chapter IV of the constitution (instructs to take efforts to protect
and improve the environment and safeguard the wildlife and forest of
the country.
• Article 51-A(g) – fundamental duties of every citizen of India (duty of
every citizen of India to protect and improve the natural environment
including forests, lakes, rivers, wildlife and have compassion for living
creatures.)

31. • CENTRAL POLLUTION CONTROL BOARD (CPCB) – September 1974,
constituted under the WATER (PREVENTION AND CONTROL OF
POLLUTION), ACT 1974. Later CPCB was entrusted with powers and
functions under AIR (PREVENTION AND CONTROL OF POLLUTION)
ACT, 1981.
• This board is led by its chairman who is nominated by central
government.
• Current active chairman – Shri S.P. Singh Parihar, IAS.
• Principle functions of CPCB –
1) To promote cleanliness of streams and wells in different areas of
the states by prevention, control and abatement of water pollution.
2) Improve the quality of air and to prevent, control or abate air
pollution in the country.

32. THANK YOU!

33. This presentation contains
• 1. types and sources of air pollutants
• 2. effects of air pollution
• 3. common devices used to control air pollution
• 4. pollution control acts in India
• 5. pollution monitoring bodies in India